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Carbaryl
Carbaryl-2D-skeletal.png
Carbaryl-3D-balls.png
IUPAC name
Other names Sevin
Identifiers
CAS number 63-25-2 Yes check.svgY
EC number 200-555-0
UN number 2757
RTECS number FC5950000
SMILES
InChI
InChI key CVXBEEMKQHEXEN-UHFFFAOYAZ
ChemSpider ID 5899
Properties
Molecular formula C12H11NO2
Molar mass 201.22 g/mol
Appearance Colorless crystalline solid
Density 1.2 g/cm3
Melting point

142 °C

Boiling point

decomposes before boiling

Solubility in water very low
Hazards
MSDS ICSC 0121
EU Index 006-011-00-7
EU classification Carc. Cat. 3
Harmful (Xn)
Dangerous for the environment (N)
R-phrases R20/22, R40, R50
S-phrases (S2), S22, S24, S36/37, S46, S61
Flash point 193–202 °C
 Yes check.svgY (what is this?)  (verify)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Carbaryl (1-naphthyl methylcarbamate) is a chemical in the carbamate family used chiefly as an insecticide. It is a colorless white crystalline solid commonly sold under the brand name Sevin, a trademark of the Bayer Company. Union Carbide discovered carbaryl and introduced it commercially in 1958. Bayer purchased Aventis CropScience in 2002, a company that included Union Carbide pesticide operations. It remains the third-most-utilized insecticide in the United States for home gardens, commercial agriculture, and forestry and rangeland protection.

Contents

Production

As in the Bhopal disaster, carbaryl can be produced by reacting methylamine (1) with phosgene (2), undergoing elimination to give methyl isocyanate (3). Methyl isocyanate reacts with 1-naphthol (4) to give carbaryl (5):[1]

Preparation of carbaryl as in Bhopal.png

An alternate synthesis which bypasses the toxic methyl isocyanate reagent exists: 1-naphthol (1) is reacted with phosgene (2) to give the chloroformate (3), which reacts further with methylamine to give the desired product (4):[1]

Alternative synthesis of carbaryl.png

Biochemistry

Carbaryl is a cholinesterase inhibitor and is toxic to humans. It is classified as a likely human carcinogen by the United States Environmental Protection Agency (EPA.)[2] It kills various beneficial insect and crustacean species along with intended pest victims, so care must be taken when spraying where beneficial nontarget species are present. Carbaryl is acutely toxic to honeybees, destroying colonies of bees foraging in an area where the chemical has been applied.

Oral LD50:

  • 250 mg/kg to 850 mg/kg for rats
  • 100 mg/kg to 650 mg/kg for mice

When ingested by people it is metabolized rapidly and excreted in the urine.

Active Ingredient in Carylderm (R) shampoo used to combat head lice
In Austria, the pharmacy will sell, without a prescription, this shampoo containing 1 gram Carbaryl per 100 gram shampoo. Treatment for head lice involves shampooing on days 1, 3, and 7 until infestation is eliminated.


Carbaryl is illegal in several countries, including the United Kingdom, Austria, Denmark, Sweden, Germany and Angola.[3 ]

References

  1. ^ a b Thomas A. Unger (1996) (Google Books excerpt). Pesticide synthesis handbook. William Andrew. pp. 67–68. ISBN 0815514018. http://books.google.com/books?id=blYN-_pY9_IC&pg=PA67.  
  2. ^ Interim Reregistration Eligibility Decision for Carbaryl, U.S. EPA, June 2003.
  3. ^ Carbaryl Insecticide Hazard Data

External links

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